Circuit/System Description
WARNING: This page is about a different car, the 2011 Cadillac DTS. However, it is still accessible from the selected car via links, so may be relevant.
The knock sensor (KS) system enables the control module to control the ignition timing for the best possible performance while protecting the engine from potentially damaging levels of detonation. The engine control module (ECM) monitors 2 separate KS, located under the intake manifold. The KS produces an AC voltage signal that varies depending on the vibration level during engine operation. The control module receives the KS signal through 2 isolated signal circuits. The control module adjusts the spark timing based on the amplitude and frequency of the KS signal.